Centrifugal pump



My 8, 1934 v. .1. MILK'owsKl 958,108

CENTRIFUGAL PUMP Filed Feb. l5. 1930 3 Sheets-Sheet l Elfi. 3

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Swanton dnne# 5 May 8, 1934. v, J. MILKowsKl CENTR I FUGAL PUMP FiledFeb. 15. 1930 3 Sheets-Sheet 2 dum/wu; S

May 8, 1934 V. J. MILKowsKl 1,958,108

CENTRIFUGAL PUMP Filed Feb. l5, 1930 3 Shee'cs--Sheecl 5 gfx/ventendbtozwuff Patented May 8, 1934 UNITED STATES PATENT OFFICE 1 Claim.

l.10 eject any harmful material which may lodge between the impeller andthe lining of the pump. Another object of the invention is to enablestud bolts to be connected with parts constructed of very hard andalmost unmachineable material,

, 15 without requiring the tapping of screw threads therein. A stillfurther object of the invention is to provide an improved constructionof sealing ring and pump shell cover, whereby the joint between theshell and the hub of the impeller is rendered leak-proof and thewearable parts capable of being replaced inexpensively.

In the accompanying drawings:

Figure 1 is a vertical, longitudinal, axial section through the pump.

Figure 2 is a vertical, transverse medial section thereof taken on line2--2, Fig. 1.

Figure 3 is a vertical transverse section through the pump taken on line3 3, Fig. 1.

Figure 4 is a front elevation on a reduced scale of the pump casingcover.

Figures 5 and 6 are front elevations respectively on a reduced scale ofthe main body and the lining plate of the pump lining.

Similar characters of reference indicate like parts in the severaliigures of the drawings.

To the upper face of a foundation frame or sub-base l0 is secured anannular main casing or pump shell 11 which is preferably provided withdownwardly and outwardly projecting integral feet or base flanges 12@Land 12b whereby it is suitably secured to the sub-base l0. Said -pumpshell, as best shown in Fig. 3, is made up of two sections; viz, anupper shell section 13 and a lower shell section 14, the joint or di- 45vision line between the same being horizontal and in a plane with theaxis of the built up shell 11 taken as a whole. Said upper and lowershell sections are detachably secured together by securing bolts 15which pass vertically through 0 suitable, outwardly projecting, flanges16 and 17 formed integrally with their respective shell sectionsadjacent their meeting edges.

The vertical, flat, rear wall 18' of said pump shell 11 comprises upperand lower sections which 5 are formed integrally with said shellsections 13 and 14 respectively, as is likewise the peripheral orcylindrical shell wall 20. The vertical flat front wall 21 of the shellis, however, separate from said shell sections and constitutes the innerwall or rear portion of a closure member or shell cover 22, the samebeing suitably and detachably secured to said shell sections by means ofan annular row of stud bolts 23 which pass through suitable holes insaid shell cover and are threaded into the shell sections. The centralpart of said shell cover 22 is axially tubular and constitutes an inletduct 24 which communicates at its rear or inner end with the hollowinterior of the pump while its forward end is flanged at 25, or isotherwise rendered capable of being tubularly 7@ connected with asuitable suction pipe line adapted to supply the pump with the fluid(and more or less gritty) material being pumped.

The rear vertical wall 18 of the shell is bored out or otherwisemachined at its inner part so 75 as to provide a rear, cylindricalfemale contering surface 26 which is longitudinal and coaxial with theaxis ci the pump shell l1. The outer front part of said pump shell isalso bored out or otherwise machined to provide a similar, but largerdiametered, front, cylindrical, female centering surface 27 which,incidcntly, serves to center the cover 22. Disposed within the pumpshell is an annular lining which is constructed of very hard material,so as to withstand the heavy abrasion which is inevitably incident tothe pumping of gritty material. This lining consists of a main liningbody 28 and a lining plate 33. The main body 28 of the lining coversover and thereby protects the rear, flat, vertical wall 18 v90 of thepump shell and also the peripheral wall 20 thereof. Said main liningbody 28 is adapted to be replaced when excessively worn, this beingaccomplished by iirst lifting off the upper shell section 13 from thelower shell section 14 and v95 then taking out said main lining body 28and replacing it with a new one. Said main lining body is provided onits outer rear face with a rearwardly projecting, coaxial flange whoseouter cylindrical surface constitutes a rear, male, centering surface 30which is adapted to be received within and centered by the aforesaidrear female centering surface 26 of the pump shell 11. The outer, frontend of said main lining body is similarly provided with a front,outwardly projecting, coaxial, male, centering surface 31 which isreceived by the aforesaid front, female, centering surface 27 of saidpump shell. By reason of these two pairs of centering surfaces, the mainlining body is easily and definitely positioned so as to be accuratelylocated coaxially within the pump shell.

The vertical, annular front flange face of said main lining body 28 isnishnachined and bears against the inner or rear vertical face of theshell cover 22, and is held firmly in engagement thereagainst by meansof an annular row of clamping screws 32 which are longitudinally andforwardly threaded through the vertical rear wall 18 of the pump shell(see Figs. 1 and 3) andbear with their front ends against the adjacentvertical rear face of said main lining body 28. The front wall 21 of theshell (i. e., the inner portion of the cover 22) is protected by alining plate 33 which is located in its proper coaxial or centralizedposition by means of its finish machined outer, annular edge 133 whichis snugly received within the finish-machined bore 134 of the verticalfront flat wall of the main lining body 28.

Said lining plate 33 is secured to the cover by an annular row of studbolts 34, whose inner ends are secured to said lining plate and whoseShanks pass through said cover with their stud nuts bearing against theouter face of said cover. But this lining plate (as also the main liningbody 28) is constructed of very hard and tough material, such asmanganese steel, and it is, therefore, uneconomic to tap screw threadsinto the same. Because of this diiculty, resort is had to an annular rowof drawing heads 35 which are constructed of relatively soft materialwhich may be easily tapped. Each drawing head is cast in a companionlocking hole 36 in the outer or front face of said lining plate 33.Thereby each of said soft drawing heads 35 is made an integral part ofsaid lining plate. The central part of each drawing head 35 is providedwith an internal screw thread which receives the rear or inner end ofits companion stud bolt 34, thereby securing said stud bolt to thelining plate 33, the latter' being thereby detachably secured to theshell cover 22.

Secured coaxially to the rear central part of the pump shell ll is abearing sleeve or hub 37 within whose bore is disposed preferably aspecial type of bearing 38 constructed of rubber composition as shown. YRotatably arranged within said bearing is an impeller shaft 40, the endthrust of which is carried by an outboard thrust-and-radial bearing 4lmounted on a base or pedestal 42. To obtain absolute rigidity, thelatter is secured both to the subbase l() and also (through theintermediary of a brace connection or spacer 43) to the pump shell 11.

Secured to the front end of said impeller shaft 40 (and preferably inthe manner shown, with the taper, key and lock nut) is an impeller 44comprising annular and laterally extending, front and rear impellerflanges 45 and 46, and spiral impeller vanes 47 which are formedintegrally and longitudinally between said flanges in the usual and wellknown manner.

Particularly when the pump ceases operation, a. certain amount ofabrasive material is apt to drop in between the outer faces of theimpeller flanges 45, 46 and the inner faces of the pump lining(comprising the main lining body 28 and the lining plate 33). Underthese circumstances and if the construction is such that the clearancebetween these faces is very small, then, when the pump is started up,the abrasive is dragged around a considerable length of time beforebeing expelled, and this causes a consider able amount of destructiveabrasion. The present invention avoids this difficulty by providing anadequately large (though not very considerable) clearance between thesaid impeller flanges 45, 46 and the inner faces of the pump lining and,at the same time, providing a set of shallow but effective front andrear ejection vanes 50 and 5l which are of the same spiral form (asshown in Fig. 2) as the main impeller vanes 47, and are formedintegrally on the outer faces of the front and rear impeller flanges, 45and 46 respectively. These ejection vanes operate in the same manner asthe main impeller vanes 47 except that they do not handle anyconsiderable quantity of material. The interior of the pump lining lyingcircumferentially outside of the impeller may be denominated the volutechamber' 52 which is under pressure when the pump is in operation andthis pressure is prevented from working inwardly between the impellerand the pump lining by reason of the centrifugal action of said ejectionvanes, which clear their paths of and throw out all liquid and solidmatter, whenever the pump is operating. This construction also preventsany viscous friction due to the presence of liquid between the impellerand the pump lining, the overall length of the entire impeller includingthe depths of these two sets of ejection vanes being approximately equalto the width of the said volute chamber, so that liquid or othermaterial thrown out by said ejection vanes is centrifugally dischargeddirectly into said volute chamber.

A replaceable annular throat liner or ller ring 53 is pressedlongitudinally forwardly against and rigidly secured to the rear face ofthe pump cover 22 by means of an annular row of longitudinal adjustingscrews 54, the bore of said filler ring being flush with the inlet duct24 of said cover and being curved to direct the material from said inletduct rearwardly and outwardly into the central part or receiving opening55 of the impeller. The forward, central part of the impeller isprovided with a forwardly projecting, coaxial, annular flange 56 whichembraces the rear part of the periphery of the filler ring 53. A packingor sealing ring 57 is arranged with a push fit on the periphery of saidfiller ring, its rear flat face being disposed transversely of the pumpaxis and bearing against the flat, front face of the flange 56 of theimpeller. Said sealing ring is not rotatable, but is capable of beingadjustably moved longitudinally toward or away from the front face ofsaid impeller flange 56 of the impeller. For advancing or movinginwardly said sealing ring 57 the lock nuts 60 of the draw screws 6l andthe lock nuts 62 of the adjusting screws 54 are first slackened. Thenthe adjusting screws 54 are tightened until said sealing ring bearsrearwardly sufficiently hard against the front face of the impellerflange 56 so as to make a fluid-tight joint therewith. 'Ihis action ofthe adjusting screws is due to the fact that the inner ends or faces ofthe adjusting screws 54 bear against the front face of said packingring, while their inner periphery portions are in screw threadedengagement with the filler ring 53. The central portions of saidadjusting screws are slidably received within suitable holes 59 whichpass longitudinally through the wall of the casing cover 22. Thus whenthe adjusting screws 54 are advanced, their inner ends force the sealingring 57 rearwardly relative to the filler ring 53, and then when theadjusting screw lock nuts 62 are drawn up tight, they act to solidlyclamp the said filler ring outwardly against the inner face of thecasing cover 22. When it is desired to loosen or retract the sealingring 57, the adjusting screws 54 and their lock nuts 62 are rstslackened, and then the lock nuts 60 of the draw screws 61 are thentightened until the desired outward movement of said sealing ring hasbeen obtained. Thereupon the adjusting screws 54 are again advanced, toact now n the capacity of set screws whereby said sealing ring, packingring and cover are all clamped solidily together.

The operation of the pump is as follows:

The fluid (and more or less gritty) material being pumped enters thepump through the inlet duct 24 and is thrown outwardly by the impeller44 into the volute chamber 52 and thence into discharge duct 63. Theprevention of leakage between the outer, front face of the impeller 44and the said inlet duct 24 is effected by means of sealing ring 57 whichmay be adjustably moved toward or from the front, iat face of theimpeller ange 56, by screws 54 and 61. Wear between the impeller and thefiller ring 53 and between the latter and the sealing ring 57 is caredfor by merely inexpensively replacing said filler ring 53 withoutrequiring that the entire casing cover 22 be replaced. Any materialwhich may accidently fall in between the impeller 44 and the lining isinstantly thrown out by ejection varies 50 and 51. The main pump liningbody 28 and the lining plate 33 are so constructed that they have nolateral or transverse joints which would operate to interfere with theflow of material through the pump. The main pump lining body 28 is easyto replace as it is centralized at opposite ends by the companion frontcentering surfaces 27 and 31 and companion rear centering surfaces 26and 30 in which position it is then clamped by clamp screws 32.

I claim as my invention:

A centrifugal pump comprising a shell; an impeller arranged therein; alining plate constructed of hard material and having a locking hole; adraw screw threaded through said shell and having its inner threaded enddisposed within but not touching the sides of said locking hole; and adrawing head constructed of relatively soft material and disposedbetween the interior face of said hole and the exterior threaded face ofsaid draw screw.

VICTOR J. MILKOWSKI.

